This invention relates to a method of imparting antistatic properties to fabrics, which consists in treating fabrics with an antistatic amount of isostearic acid during laundering with a nonionic detergent at a maximum pH of 8, said isostearic acid being separately added during the wash cycle.
Synthetic fabrics are very prone to develop a static electrical charge from friction, as during tumble drying after laundering, or in normal use or wear.
The use of various and diverse chemical materials and particularly cationic quaternary ammonium compounds as softeners and antistatic agents for textile products is very well known in the art. It is also well known to employ such materials for their antistatic and softening effects during the laundering operation and particularly in the rinse cycle of the laundering process. This latter technique has been necessitated by the fact that the aforesaid quaternary compounds heretofore employed, being mainly cationic in nature, were not compatible with the anionic detergents, one of the major types of detergents used in the washing cycle.
In addition, the usual quaternary ammonium salt antistatic agents have limited effectiveness in all-nonionic detergents.
It is also well known that there is a tendency for laundered articles to yellow or discolor when treated with aforesaid quaternary compounds.
Another disadvantage associated with the use of said cationic agents in the laundering of fabrics therewith is its interference with the deposition on the fabrics of optical brightener, thereby reducing optical brightener performance of a detergent composition containing said optical brightener.
Still another disadvantage of the cationic quaternary ammonium antistatic softeners is its interference with the cleaning properties of the detergent by reducing the soil removal effected by the detergent, resulting in decreased washing effectiveness. The presence of the anionic detergent material substantially negates the fabric softening properties of the cationic quaternary ammonium compounds as well as counteracts the minimal antistatic activity possessed by said quaternary compounds.
Accordingly, aforesaid quaternary agents have been combined with an alkyl ethanolamide in the rinse cycle in order to provide antistaticity to synthetic fabrics such as nylon, as shown in U.S. Pat. No. 3,451,927.
U.S. Pat. No. 3,954,632 discloses a fabric softening and antistatic composition compatible with anionic, nonionic and ampholytic detergent compositions comprising a particular smectite clay material, cationic antistatic agents and acidic compatibilizing agents such as fatty acids, to be used as an additive to the laundry washing bath.
Fatty acids have been used in liquid detergent compositions comprising mixtures of anionic and nonionic surfactants as a corrosion inhibitor, shown in U.S. Pat. Nos. 4,079,078 and 4,105,592; as cleaning enhancers in the absence of builders, shown in U.S. Pat. No. 4,285,841; as stability agents in enzyme-containing detergents, shown in U.S. Pat. No. 4,287,082; and as a major ingredient together with a nonionic surfactant to yield better overall washing efficiency in laundry operations, shown in U.S. Pat. No. 3,953,351.
Isostearic acid has been used in an oil/water skin cream composition as a dispersing agent in said oil phase, shown in U.S. Pat. No. 4,087,555; as one component in a four component emulsifying or solubilizing composition, shown in U.S. Pat. No. 4,097,403; and as a conditioning agent in conjunction with a surfactant in shampoo compositions, shown in U.S. Pat. No. 3,590,122.
U.S. Pat. No. 3,625,905 discloses a cleansing and softening composition for fabrics comprising a noncationic surfactant and an alkali metal isostearate salt as the softening agent.
However, none of the prior art discloses the method of treating fabrics with isostearic acid during the wash cycle to impart antistatic properties to fabrics laundered with nonionic detergent.